OBJECTIVES: Major emphasis is placed upon the study of tumor antigens of the transplantation rejection type (TSTA) and of the immune responses they evoke. As a corollary to this study the biologic properties in vitro and in vivo of Histocompatibility (H-2) antigens are under study. Solubilization and methods of purification of both TSTA and H-2 are under investigation with the ultimate purpose of defining these membrane antigens in physicochemical, biologic and molecular terms. BIBLIOGRAPHIC REFERENCES: Henriksen, O., Law. L.W. and Appella, E.: Quantitative in vivo characterization of soluble SV40 tumor specific transplantation antigens (TSTA) of the mouse. J. Nat. Cancer Inst. 58:1785-1788, 1977. Pardarathsingh, M.L., McCoy, J.L., Dean, J.H., Lewis, D.D., Northing, J.W. and Law, L.W.: Examination of general and tumor-specific cell-mediated immune responses in mice bearing a progressively growing plasmacytoma. J. Nat. Cancer Inst., 58: 1701-1707, 1977.